Intersection of tori fails to produce results

When intersecting two tori GeomAPI_IntSS may either miss part of the possible result or fail to produce result at all. Missing result is usually a circle of radius equal to minor radius of tori lying in the plane perpendicular to tori plane and passing via their locations - see attached screenshot.

Case A:
torus t1 20 5
torus t2 40 0 0 20 5
intersect res t1 t2
# no resulting circle of radius 5 at the intersection of tori, only b-splines

Case B
restore b/surface1_draw s1
restore b/surface2_draw s2
intersection res1 s1 s2
# similar to above - no resulting circle, only b-splines
restore b/comp1.brep c1 - contains points along missing solution

Case C:
restore c/surface1_draw ss1
restore c/surface2_draw ss2
intersection res2 ss1 ss2
# no results
restore c/comp2.brep c2 - contains points along missing solution